This invention relates to an improved pick-off means for use in a plain paper type electrostatic copier.
Electrostatic copiers of the plain paper type, in which developed toner particle images are transferred from a photoconductive surface, such as that of a rotating drum or endless belt, to an untreated surface, such as that of ordinary paper, are known in the art. In these copiers, it is necessary to provide means for separating the photoconductive surface from the paper surface once the transfer step is completed. Where a corona charger or similar device is used to give the paper an electrostatic charge to assist the transfer process, the pick-off must overcome the tendency of the paper to cling to the photoconductive surface under the influence of the charge from the transfer device. Clinging also occurs where liquids are used to develop the latent electrostatic image as is common in the art. Pick-off means which mechanically grip the paper edges during the transfer step to provide positive separating action suffer the disadvantage of reducing the effective image receiving area of the paper. Other pick-off means which operate by introducing a sharp curvature in the path of a photoconductive belt for example do not lend themselves to use with drum-type machines.